Fosi AudioV1.0G 2 Channel Class D Mini Stereo Amplifier for Home Speakers TPA3116 50W x 2 with Power Supply

AN UPDATE:I liked this tiny amplifier so much that I bought a second one for my office computer.Previously, my main computer used a Lepai LP-2020A+ driving a set of decent bookshelf speakers, and my office computer used a set of cheap USB active speakers.Later I bought the first Fosi to replace the Lepai on my main computer system, and it worked out beautifully (see the ORIGINAL REVIEW below).I decided I would use the Lepai on my office computer, and for that, I bought a set of Polk Audio T15, which are probably the cheapest slightly "serious" bookshelf speakers but should be far better than those cheap USB speakers.But within minutes of setting up the system, I felt terrible.It's not that the Lepai LP-2020A+ with the Polk Audio sounded worse than the cheap USB speakers. On the contrary, they were noticeably better. The trouble was that I started to compare the office sound with my main computer system sound, and I just couldn't help it. This is what happens when you get into a better system. It spoils you.On the office system with Lepai, everything sounded so hollow and distorted, especially the vocals and human voice recordings (not singing), which was so bad that I couldn't stand. It was painful. At first I thought it might be the Polk Audio T15s, but then I suspected it was something else, including the built-in line output, etc. Speculating all kinds of diagnostic possibilities was driving me crazy.Finally, I just gave in and bought a second Fosi, with a good DAC, planning to return the Polk Audio T15s for something better as well.Well, the Fosi and DAC came in, and I connected them to the computer and the Polk Audio T15s. What an improvement! Clearly, the Polk Audio T15s are fine (although not great). The culprit was the Lepai LP-2020A+ amplifier, as the Fosi made a huge difference.The following is the original review I wrote after about the first Fosi:ORIGINAL REVIEW:Unbelievable value for a small desktop setup or computer sound system. Everything is perfect. The sound, the functions, the build quality, and the appearance.This replaced my seven-year-old Lepai LP-2020A+, which actually had quite good sound on my computer sound system as well, but left me wanting a bit more. One of the obvious issues with Lepai was the highly noticeable noise floor when the volume is turned past 50%. Although I seldom turn the volume past 50%, the limitation is bothersome. After seeing some reviews on the TI TPA3116D2 chip, I decided to upgrade, to just give me a bit more peace of mind.And I am very satisfied. The Fosi sounds great. To be honest, I did not do a side-by-side comparison with the Lepai, but I am pretty sure Fosi delivers cleaner and fuller sound.The noise floor is much lower. It is quite low even if you turn the volume all the way up to the maximum. On my desktop speakers, I can hear no noise when the volume is below 30%. Once it passes the 30% level, the noise floor steps up abruptly, but strangely enough, it stays quite flat after that and does not further increase too much even if you turn the volume all the way to 100%. Even at the maximum level, the noise is only slightly noticeable when I sit about five feet away from the speakers. This is a near-field environment, and I'm fairly picky about the noise, but still, this is completely manageable. A day-and-night difference compared to Lepai LP-2020A+.Fosi comes with a rather large power supply, which may seem unnecessarily large, but is necessary for its 50W x2 power rating. When it comes to power, you simply don't have any way to cheat. For example, having a 30 W power supply for 50 W x2 = 100 W amplifier will inevitably lead to insufficient amplification and distortion at higher volumes.Also, the fact that Fosi has five-way binder posts for speaker connectors is a plus, much better than Lepai's primitive clippers.I did hesitate in choosing between the Fosi (this unit) and Micca OriGain A250 or OriGain AD250. OriGain A250 is $20 more expensive, not a lot in the dollar amount, but one-third (33%) more in relative terms, which becomes a matter of principle, if not affordability.Still, I almost got OriGain A250 instead of Fosi V1.0 because the A250 has slightly better user review ranking, and I desired peace of mind. But then I saw reviews that mentioned OriGain A250's having heavy bias on the left channel at low volume level. That bothered me as I usually listen to background music at quite low volume levels.OriGain AD250 had its own attractions because it had a built-in ADC and USB sound input. However, in the end, I decided not to go that route because integrating ADC may appear convenient now but could be an invitation for trouble further down the road. What if the built-in ADC develops problems? (I did see one reviewer mentioning OriGain AD250's built-in ADC has a signal synchronization problem). Or what if you want to upgrade ADC? Etc.Anyway, I'm glad I settled on the Fosi. It leaves me wanting nothing more for my computer-based desktop system.

So, I bought this little unit in 2020… 4 whole years ago… and finally found the time and the need to use it.Boy am I pleasantly surprised.Paired with my various Klipsch speakers (mostly using my giant corner horns at the moment), this amp sounds amazing. It really does. And I'm quite nitpicky when it comes to sound quality. I'm used to various amps, including vintage Sansui, Marantz, Kenwood receivers and vintage and newer Mcintosh, which all sound different. I'm using an (too expensive) ADI 2 Pro DAC converter that has phenomenal sound reproduction characteristics, so if the end result is anything less than great, it's this little amps fault. I'm glad to say that it sounds very crisp and clean, very much like the Sansui AU-919, which was designed to provide very faithful reproduction of the original music. In fact, it sounds just as good as my AU-919. It is the exact opposite of the "warm tube amp" sound, similar to the sound that Marantz and Macintosh amps are known for. If that's the sound you're looking for, this isn't the amp. You could use a preamp to tweak the sound, if you wanted to, I suppose.The most important thing to remember is that this amp is "only" 50 W, so the more efficient your speakers, the better the sound is going to be. Klipsch speakers can get very loud with just a couple of watts of power. I have a 17 W tube amp and I can't turn the volume more than 50% or the sound will be so loud it's unbearable. So 50 W for my speakers is more than enough. If you have speakers that NEED 50 W, you probably will need something more powerful… and there are different models of this amp that will work better for you.This amp would be perfect with a surround sound system… One amp for each channel. Now that I know how well this unit works, I will definitely be buying a couple of more of them to add additional speaker pairs.I've seen some others say that their unit gets really hot. Mine doesn't… not at all. Probably because I'm not using all 50 W. This goes back to pairing it with the right speakers. I set the volume on the amp to 50% and then adjust the input to get additional volume. If you are having to run the volume on the amp at 100% all the time, you definitely need an amp with more power… 100 W or more.

This output amplifier works very well. It produces plenty of drive power for my stereo speakers. The sound quality is very good, no noise, no hum. Most amazing are the tiny size and weight, due to the switching technology. It is difficult to believe the difference in the bulk of the original linear amplifier and this one. One possibly weak point is the internal gain. I use it with the internal gain turned to the maximum. My sources of signal do have enough range in amplitude to supply this one.

I bought this as a replacement for the 100w unit that went bad after about 3 years. Sound quality is very good, cleaner than other studio amps I've used. Bought the 50w this time because I didn't need all that headroom and the 100w ran a bit hot. This 50w does not. In fact it's almost room temp. It powers 2 Mackie studio monitors w/ 8" woofers.

Took a gamble on a brand not well known in audio and for $50 my gamble was well worth it! I use it as an amplifier from my vinyl record player to my two bookshelf speakers, and i couldn’t have been more impressed with the ease of use and sound quality i got from it. As I’m relatively new to vinyl listening, I needed something small that went from rca to speaker wire, and I didn’t really care for all the bass treble stuff. As cool as it would be in the future, more moving parts leads to more ways to failure. So i fell on this little guy. Very solid and not cheap feeling, and nice rubber feet on the bottom to keep it from sliding around. Volume knob and the on and off switch feel nice. The speaker wire outputs support banana plugs, which is a nice to have. Theres not a lot to say about it besides that it works wonderfully at the moment, hopefully time proves to be fruitful.